The 3 wheeled Wonder

Back in 2011 during our second year of Engineering, we( me , Sanket and Dhruv ) had ventured out to build our first robot together as a team. To tell a bit about us, me and Sanket hadn’t even touched so much as a line-follower before. Automata was an event in which we had to manuever the Robot via Image Processing by an overhead camera through a hexagonal grid. The path was pre determined and was given to us as a text file. None of us had the faintest idea of Image Processing and I ended up writing this horrible piece of Matlab code that I haven’t seen since then because I’m too ashamed of it. But never the less, it worked on the day of the competition. But more than the code, we owe our victory to the unique design of our robot. I still remember how overjoyed we were when for the first time the robot took a turn on its own ( guided by the computer ). The eventual result of the contest was beyond our wildest dreams.

The Robot

I have roughly sketched up the top view of the robot here.
Robot Sketch

The omni-wheels used are similar to the one in this picture


Since the grid was hexagonal the three omni-wheels provided a unique advantage. The robot could navigate in 6 directions without rotating about itself. For instance, by keeping wheel A fixed and rotating B and C together, the robot could movie in direction 1 or 4.

Thus, we could complete the assigned task, without turning the robot. This saved time, and also eliminated the Image Processing needed to compute the orientation. All we needed to do, was turn the right wheels and the robot moved in one of 6 directions.

So on the whole, the computer saw the grid, read the sequence from the text file, and instructed the robot accordingly to do the needful ( go, stop or change direction ) via Bluetooth.We were banned from relying on position encoders, so the Computer had to decide, by processing images, when the robot had arrived at the center of one hexagon and had to move to the next. The result as you will see, is in the following video.


One thought on “The 3 wheeled Wonder

  1. Pingback: GSoC 2014 – Signing off | A Simple Progammer's Blog

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